Taxol, Estrogen Receptor Status, and Glutamine

[gail23]

I am 50 and in 2000 had lumpectomy & radiation on rt breast for DCIS. In Dec 03 a surgical biopsy of lump in left breast found infiltrating ductal cancer. A subsequent core needle biopsy on another 'suspicious' area also showed invasive lobular. I had mastectomy & sentinel lymph node biopsy. One lymph node was + so axcillary was later done but no more positive nodes were found. Pathology report states ER positive, PR negative, HER-2/neu negative (+1), tumor 1 cm, final grade III. No radiation was done. I have completed 4 cycles of AC. My oncologist now wants me to do 4 cycles of Taxol every 3 weeks and then Tamoxifen. I am VERY worried about side effects of Taxol particularly the peripheral neuropathy which can be very severe and can be permanent. First question is how can I determine the amount of benefit I may get from Taxol in my particular case & does it out weigh the severe side effects because I have read conflicting reports of a study (CALGB study 9344) which some say shows Taxol has NO significant benefit to ER positive cancers like mine (http://www.jco.org/cgi/content/full/21/23/4465)? Has this been resolved? If Taxol only improves my chances of survival very slightly it hardly seems worth it. If they can't agree, how do I determine what percent benefit I might expect to decide whether to take the Taxol? I have also read conflicting information as to whether taking Glutamine can reduce the peripheral neuropathy. Do you have any info or recommendation as to whether Glutamine helps and should it be taken with the Taxol? Thank you!

[CCF-RN,MSN-rf]

Dear Gail23:  In 2004, AC + Taxol has become the standard of care for aggressive or high risk cancers.  This is based on group data of course.  Current research is focusing on the issue of dose dense (every 2 weeks) AC+T versus standard dosing (every 3 weeks) AC+T in high risk breast cancer.

Attempting to determine individual benefit versus risk is nearly impossible.  You have some good prognostic features (ER +, HER2 -)and some higher risk features (+ node and grade 3).  So, your risk is higher than some but certainly not the highest.  Further, we cannot predict individual responses to treatment.  Most women do not have severe or permanent peripheral neuropathy from this regimen.  But the possibility exists and would be more likely if there are preexisting neuropathies, diabetes, or other medications that would contribute to neuropathies.  The article you site is more of an editorial opinion (published in 2000) that, to my knowledge, has not been widely accepted.  This "critique" is part of the peer review process that all published research undergoes.

Regarding Glutamine.  There is one study looking at Glutamine to prevent neuropathy in those undergoing high dose taxol.  There was some small benefit but cannot be translated easily to the doses that are used for adjuvant therapy in breast cancer.  These doses are lower.  This concept needs to be better investigated before a sound recommendation can be made.

Finally, if you decide to proceed with the taxol, you should keep your health care professionals informed of any side effects you experience (including any peripheral neuropathy).  Doses can be reduced or the medication stopped if it appears that the risk will be greater than the benefit for you.

[gail23]

Thank you very much for your reply. I'm not sure what the publish date of 2000 that you mentioned in your answer pertains to. The link that I mentioned takes me to a page that references the "Journal of Clinical Oncology, Vol 21, Issue 23 (December), 2003: 4465". The first sentence in the article states "An important finding indicating a difference in tumor biology in estrogen receptor (ER)-positive versus ER-negative breast cancer seems to be downplayed in the long-awaited publication of the Cancer and Leukemia Group B Trial 9344 on March 15, 2003." I took that to mean the study results regarding estrogen receptor were published in 2003 but maybe I have misinterpreted this. At any rate I understand your answer to mean that the difference in estrogen receptor status is not widely accepted to affect outcome.